In dentistry a variety of devices are available which allow for preparation and/or application of dental materials in a dentist's practice. In particular for preparation of materials that are typically used at larger amounts, like for example dental impression materials, devices have been developed that provide for automatic dispensing from packages and/or for mixing of such materials. An exemplary device for mixing and dispensing a dental impression material is for example available under the designation 3M™ ESPE™ Pentamix™ from 3M ESPE AG, Germany. Typically such a device allows for two material components to be simultaneously supplied from a package through a mixer where they are mixed. Often the devices provide for continuously extruding the components through a mixer, where the components are mixed as the components flow through the mixer and released from an outlet.
The devices further typically have a motor driven piston for extruding the material from a container. A variety of different drive concepts have been proposed for driving the piston at a relatively high force as it may be required for appropriately dispensing the dental material.
For example EP 1 700 639 discloses a device for dispensing a flowable substance. The device comprises at least one force transmitting member (for example a push-pull chain) adapted to transmit a pushing force in a direction toward or opposite the substance and which can be gathered non-linearly.
Although there are a variety of devices on the market which provide for automatic mixing and dispensing there is still a desire to minimize costs for manufacturing of such devices and for providing the devices with maximized reliability.